The canonical "founding father" of free/open software dual licensing among FOSS wonks is L. Peter Deutsch, of Ghostscript fame. His companies ran a number of bu

The canonical "founding father" of free/open software dual licensing among FOSS wonks is L. Peter Deutsch, of Ghostscript fame. His companies ran a number of business models in their early days, dual licensing among them. The canonical "popularizer" is probably MySQL AB, followed by Trolltech/Qt. These days, Open Core is riding high. Dual licensing also had its day, and may again. The more general pattern of "free under these public terms, else pay us" for software goes back far further. Mosaic and Navigator were early Web-enabled examples. Before that, some "shareware" traded on physical media was feature-complete and unlocked, but license-limited, on the honor system. Outside of software, in other media covered by copyright, the model is old as the hills, and far older than the Free Software movement. Especially with noncommercial terms for free use.